A blood pump has been designed which appears to be particularly appropriate for both extracorporeal and totally implanted prolonged assisted circulation. Special features include energy transmission by magnetic coupling, which eliminates direct wire contact from the electrical power source to the pump, and permits the drive and control unit to be physically separated from the pump. Other virtues of this system appear to have successfully resolved problems related to hemolysis, in vivo heat rejection, simple external control, adequate pressure flow capacity (20 L/min against 500 mm Hg), compact size, light weight, and ease of implantation. Currently proposed research includes the further development and testing of this system in an extracorporeal position to produce prlonged pulseless total body perfusion in the calf. Particular emphasis will be placed on the study of blood trauma under prolonged high shear stress exposure, initiation of the clotting mechanism and trial and evaluation of non-thrombogenic surface materials.